THE Veterinary Services Division of the Ministry of Agriculture & Fisheries continues its investigations into the illness and subsequent death of horses at Caymanas Park, St Catherine, starting on May 1.

A preliminary/presumptive diagnosis of monensin (ionophore) toxicosis was made based on history and clinical signs exhibited by the affected horses.

Investigations revealed that horses from some stables at Caymanas Park became ill within hours after ingestion of concentrate feeds manufactured by Hi Pro Feeds Limited.

The animals exhibited colic-like symptoms with ataxia, inco-ordination, depression, recumbency and death. Twelve horses have been confirmed dead of an estimated number of 30 affected horses.

Samples of the feed were collected from different locations at Caymanas Park for laboratory analyses. In four of five feed samples collected, contamination with narasin was detected. Three horses from a stable where the animals had consumed concentrates containing narasin at the level of a maximum of 97g/ton of feed subsequently died.

Narasin, like monensin is an ionophore, which is added to broiler chicken feeds at concentrations of up to 70g/ton for the prevention of coccidiosis. Ionophores are antibiotics, which are used as coccidiostats and growth promotants in veterinary medicine. Narasin, monensin, lasalocid, maduramycin and salinomycin are the most commonly used ionophores incorporated in feeds.

Horses, cattle, turkeys, dogs, cats, rabbits and rats are sensitive to ionophore toxicosis. Ingestion of narasin by these species has proved to be fatal.

Samples of organs such as lung, heart, liver, spleen, kidney and skeletal muscles were collected for histopathological examination. In addition, further analyses of feeds for mycotoxins, pesticides and microbial contamination continue.

The Veterinary Services Division continues to evaluate operations at the Hi Pro Feed mill and is in constant dialogue with the management of Hi Pro to ensure that all the contaminated feed is identified and recalled.